• Age 16 years or older, with a documented diagnosis of sickle cell disease (HbSS, HbSC, HbS/β0 thalassemia, HbS/β+ thalassemia, or other sickle cell syndrome variants)
  • At least 2 and no more than 10 sickle cell pain crises in the past 12 months prior to informed consent
    • Defined as acute episodes of pain, acute chest syndrome, priapism, or hepatic or splenic sequestration
  • If taking hydroxyurea, the hydroxyurea dose must be stable for at least 90 days before randomization


  • Pregnant or breastfeeding
  • Receiving regularly scheduled transfusions
  • Hepatobiliary disorders, significant liver disease, gallbladder disease, or severe kidney disease
  • Prior exposure to gene therapy or prior bone marrow or stem cell transplantation
  • Currently receiving voxelotor, crizanlizumab, or L-glutamine
  • Currently receiving treatment with hematopoietic-stimulating agents
  • Taking strong CYP3A4/5 inhibitors or strong inducers of CYP3A4